feat(service): expand service layer with new domain operations

- Add IM service modules: audit, channel roles, custom emojis, forum
  tags, integrations, invitations, repo links, slash commands, stages,
  voice, webhooks
- Add PR service modules: review requests, templates
- Add repo service modules: contributors, release assets, git extras
  (archive, branch rename, commit extras, diff/merge, tag, tree)
- Add user service: social (follow/block)
- Add internal auth service
- Update existing service modules with expanded functionality
- Remove deleted IM modules: articles, delivery trace, drafts,
  follows, messages, polls, presence, reactions, threads

service/repo/mod.rs

@@ -1,5 +1,6 @@
 pub mod branches;
 pub mod commit_status;
+pub mod contributors;
 pub mod core;
 pub mod deploy_keys;
 pub mod fork;
@@ -7,6 +8,7 @@ pub mod git;
 pub mod invitations;
 pub mod members;
 pub mod protection;
+pub mod release_assets;
 pub mod releases;
 pub mod stars;
 pub mod stats;